Let's simplify if possible. Do you have any other sources. If so and they are also "harsh" in the highs than it is somewhere else in your system and I agree with those that you need to change out something other than your cartridge. (Probably your speakers as beryllium tweeters can be an "in your face" presentation). OTOH if other sources are merely "bright" and not "harsh" than the problem is the character of the highs not the quantity. (Probably the cartridge, Grado's are not known to be aggressive in the highs but IMO they do not have any delicacy or sweetness to the highs).
Bottom line, more input is needed.
Bottom line, more input is needed.